The subject invention concerns devices which may be added to existing slot machines to prevent the improper operation of such machines. Machines which are commonly called slot machines are gaming machines in which a person deposits a coin of a predetermined value such as a silver dollar into the coin slot of the machine. Generally, under the force of gravity the coin slot directs the coin into the entrance end of a coin track. The coin track is elongated horizontally with spaced apart upright side walls and a bottom wall which is slightly inclined downwardly from the entrance end to the exit end thereof. The coin rolls in an upright condition through the coin track and drops through the exit end thereof to strike an electrical switch which then conditions the machine for a subsequent gaming operation. In some instances such slot machines are intended to be operated by a facsimile of a coin of predetermined value within certain parameters. Generally those parameters are weight, diameter, thickness and a surface condition such as light reflectivity.
The improper operation of such slot machines generally involves a person using a slug to effect operation of the machine. Slugs are generally coin-like pieces which resemble the intended coin. They often differ from the intended coin or facsimile in one or more of the noted parameters. Some are thinner, or are dished or slightly concave as a slug sheared from a metal sheet by a punch press, or have a different surface light reflectivity from the parameter of the intended coin. Another improper operation of such slot machines can be effected by using an intended coin attached to a thin string. The string can be used to prevent the coin from dropping into a coin collection box after the electrical switch which conditions the machine for operation has been engaged by the coin. By slightly pulling on the string to draw the coin upwardly and then again allowing the coin to descent toward the electrical switch, the machine can be repeatedly conditioned for operation with the same coin.
Many devices are known in the prior art for testing or determining the various parameters of coins. Most of that art has developed with the growth of coin operated vending machines. In the vending machine art it is necessary or desireable that the machine detect and count coins of various denominations for the purposes of totaling the amount required for vending of a product and for returning any excess amounts. It is further important in the vending machine art that the machine not be disabled upon detecting a slug because vending machines are often placed at locations remote from readily available machine maintenance personnel. Therefore coin detection mechanisms for vending machines are designed to avoid any shut down of the machine, but to direct any coins detected as non-genuine to a coin reject slot while maintaining the operability of the machine. The known devices for coin detection of the vending machine art are not appropriate for the gaming machine art because gaming machines are generally designed for operation with a coin of one denomination and are placed at locations where maintenance personnel are readily available. In the gaming machine art it is desireable that the use of a slug or object other than that intended for operation of the machine result in a shut down of the machine with the initiation of some audible or visual alarm.
It is the primary object of the present invention to provide coin or slug detection devices for gaming machines which devices will operate to test or measure various selected parameters of a coin and which shut down or prevent operation of the machine upon determining that the deposited coin does not meet one of the selected parameters.
It is a further object to additionally provide in such devices a simple means for detecting a coin with an attached string and shutting down the machine in response thereto.
It is a further object to provide such devices in a relatively simple, economical form readily adaptable to existing gaming machines.
Other objects and features of the present invention will be apparent in the hereinafter following detailed description.